In recent years, industries and academia have been making significant efforts towards development of technologies and infrastructures suitable for distributed diagnostics and home healthcare. One well-known, successful exemplary device in this endeavor is a portable glucose automonitoring device that can monitor the glucose level of the user by sampling of blood taken from a fingertip. Many efforts have been devoted to developing similar portable devices that can measure other biochemical substances. In this regime, what is needed from instrumental points of view is not high-precision, versatile measurement instruments that can detect a wide range of target analytes/substances with great accuracy, but low-cost, portable devices that can detect certain defined groups of target analytes/substances reliably and conveniently for the purpose of monitoring and diagnosing the users' physiological and biomedical conditions.
Numerous optical detection systems are in use to analyze biological specimens or other analytes. However, certain optical mechanisms require complex structures, not suited for portable devices. Especially when a higher resolution or detectability is required, it may be difficult to achieve the goal without increasing the device size or manufacturing costs.